Sea otter | Oceana Canada

Canadian Marine Life Encyclopedia

Sea otter

Enhydra lutris

Distribution

North east Pacific Ocean

Écosystèmes/habitats

Shallow, coastal waters; often found in kelp canopies

Feeding Habits

Carnivores and foragers

Conservation Status

Endangered/Threatened/Special Concern

Taxonomie

Order Carnivora (carnivores); Family Mustelidae (weasels)

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Sea otters are a charismatic marine mammal found in the north east Pacific Ocean. As a keystone species, sea otters are a critical member of the kelp forest ecosystems they live in. They are foragers, mostly eating hard-shelled invertebrates such as sea urchins. By keeping the population of kelp-grazing sea urchins to a minimum, sea otters are vital to the health and stability of the kelp forest, and in turn, all the species that depend on kelp forests for survival. Sea otters are preyed upon by bald eagles, killer whales and sharks. They also have many adorable traits, including wrapping themselves in kelp or holding hands while sleeping to keep from drifting away.

Though sea otters are one of the smallest marine mammals, they are the largest member of the weasel family and have the densest fur of any animal on Earth – with an estimated 100,000 hairs per cm2. Their fur ranges in colour from a rusty brown to black and is their primary protection from the cold water they live in. They therefore spend a lot of time cleaning their fur. They grow to be approximately 1.5 metres in length, with the females typically smaller. They spend most of their time in the water and are well adapted to swimming. They have webbed feet and strong back legs, with a large, flat head, black eyes and small ears. 

Sea otters are mammals and reach sexual maturity around 3 years of age for females and around 5-6 years for males, living to 15-20 years of age. Sea otter pups are usually born from April to July, though it can occur any time of year, and they after often born in the water! Females typically only have a single pup at a time, nursing them while floating on their backs. With a light yellowish-brown fur, pups usually only weigh around 2kg at birth.

Historically, sea otters ranged from Mexico, all the way through the north east Pacific to Japan, but they were driven to the brink of extinction by the fur trade that began in the 1700s. By 1929, they were locally extinct, or extirpated, from British Columbia. Recognized as an important species for the health of the ecosystem, 89 sea otters were successfully reintroduced to British Columbia’s Checleset Bay between 1969 and 1972. Since then, there have been ongoing protective measures, leading to a population of over 6500 – and still growing! Today, sea otters are protected by law and can be found all along the west coast of Vancouver Island and part of the central coast of British Columbia.

Though sea otters managed to survive the fur trade that almost ended them, they are still facing many threats today, including bycatch, entanglement in fishing gear, food limitation and oil spills. It is thought that oil spills pose the greatest threat due to the proximity of sea otters to major tanker routes and their susceptibility to hypothermia if their fur comes into contact with oil.

Worldwide, sea otters are listed as Endangered by the IUCN Red List. However, the Canadian population of sea otters are listed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as Special Concern.

Below is the conservation status of the Canadian population: • COSEWIC listing: Special Concern – 2007, SARA listing: Schedule 1, Special Concern – 2007

Species at Risk Public Registry. (2007). Species Profile (Sea Otter). Retrieved from http://www.registrelep-sararegistry.gc.ca/species/speciesDetails_e.cfm?sid=149 

National Geographic. (n.d.). Sea Otter. Retrieved from https://www.nationalgeographic.com/animals/mammals/s/sea-otter/ 

Leibowitz, E. (2010). Ten facts about sea otters. World Wildlife Fund. Retrieved from https://www.worldwildlife.org/blogs/good-nature-travel/posts/ten-facts-about-sea-otters

Canadian Geographic. (n.d.). Animals facts: sea otter. Retrieved from https://www.canadiangeographic.ca/article/animal-facts-sea-otter 

Fisheries and Oceans Canada. (2008). Recovering sea otters in British Columbia. Retrieved from http://www.dfo-mpo.gc.ca/species-especes/publications/sara-lep/recovering-retablissement/2008-05-eng.html 

Fisheries and Oceans Canada. (2015). Trends in the abundance and distribution of sea otters (Enhydra lutris) in British Columbia updated with 2013 survey results. Retrieved from http://www.dfo-mpo.gc.ca/csas-sccs/Publications/SAR-AS/2015/2015_043-eng.html

Fisheries and Oceans Canada. (2018). Sea Otter Research Program. Retrieved from http://www.dfo-mpo.gc.ca/fm-gp/mammals-mammiferes/species-especes/otter-loutre-eng.html 

IUCN Red List. (2015). Enhydra lutris. The IUCN Red List of Threatened Species. Retrieved from http://www.iucnredlist.org/details/7750/0 

COSEWIC. (2007). COSEWIC Assessment and Update Status Report on the Sea Otter Enhydra lutris in Canada. Retrieved from http://www.sararegistry.gc.ca/virtual_sara/files/cosewic/sr_loutre_mer_sea_otter_0907_e.pdf